This is just one question .

I had a Thread in here about getting the temperature of the house down - cheaply - and it became an interesting read with many suggestions .
However this is just a simple question about cooling down one wall .

Missy .... is out in Thailand and I ... am not .
A problem exists where one wall in particular gets slammed with sunshine all day and of course that wall becomes hot .
The heat stays in the wall well into the evening radiating heat inwards . So she needs to put something in place to cool that wall down .

From many miles away I've said to get battens attached to that wall . Vertical battens . And then attach horizontal ( fake ) planking to the battens . Covering the entire wall .
It's not planks . It's those boards that look like compressed asbestos and have a grain pressed into them to look like wood .

So my one single question is ...... do we leave it like that with a gap behind the planking ? A gap containing only air ( with an opening at the top for the hot air to escape away ) ??
Or is it significantly better to put insulation materials between the 'planking' and the solid wall ?

Which produces another question ....
Whatever the consensus is ( insulation or air ) what size of gap should go there ?
I had assumed one inch because I was thinking of one inch foam insulation panels . But maybe a bigger gap ??
Thicker foam panels . Or just a wider gap with no foam insulation panels at all ?

With appreciation .

Wasp